@philm - After this update, there have been two reports about webcam not working — this and this.
Can you please tell us which components (drivers or software) of this update might be related to this issue? I can try reverting these components. Or any other suggestion…
Thanks again for making this a brilliant OS!
I also got the same error on Kernel 5.7.14-1
And found the workaround for now on here ASUS X421IA - ArchWiki
I just had the same issue. Reading the Fedora post, they mention it being caused by unplugging a mixer which is exactly what caused it in my case.
My problem was that apparently, the graphics driver for my UHD 620 graphics chip stopped working (although video-linux was installed …). That resulted in high CPU usage of kwin_x11 on everything I did to a window in KDE and, worst of all, the wobbly window effect was gone 
The solution was to update my kernel from 4.14 to 5.4.
Please see the new Stable announcements and use those to report any issues with the update.